Character classes (like [abc]) are significantly faster than single character alternations (like (?:a|b|c)). This policy complains if you have more than one instance of a single character in an alternation. So (?:a|the) is allowed, but (?:a|e|i|o|u) is not.

NOTE: Perl 5.10 (not released as of this writing) has major regexp optimizations which may mitigate the performance penalty of alternations, which will be rewritten behind the scenes as something like character classes.


Initial development of this policy was supported by a grant from the Perl Foundation.


Chris Dolan <cdolan@cpan.org>


Copyright (c) 2007 Chris Dolan. Many rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of this license can be found in the LICENSE file included with this module